Pokémon HeartGold Version Tips

Easier Legendary Dogs Capture
To do this, you need one of the following:

1. Get a diglett
1.1. to do this (while still only in Johto), fly to the Safari Zone, and then leave that area. a bit south of it, there is a patch of grass. you will eventually find a diglett (around level 20)
2. train it to level 39
2.1. By now it should be dugtrio.
2.2 make sure it knows Magnitude and Sucker Punch (should have those 2 when you catch it)
3. Buy A LOT of repels (any type will work) and ultra balls (and other balls, i suggest Dusk Balls from Blackthorn if you do this at night)
4. Fly to either Violet, Mahogany, or Eruktec (please forgive my spelling of the city names) (not required but preferred location)
5. track the legendary dog(s) you want, having the dugtrio on top of your party.
6. when you are on the same route as one of the dogs, use a repel. move around in the grass and the pokemon you meet first (assuming repel is still active) will always be a legendary dog

this has been tested several times and it works. the repels are needed to make finding the dog easier, since except for the mt. silver area, you will not find pokemon in the wild over level 39 (which is the level of your dugtrio)

more to know:
1. use magnitude the 1st time, and if their HP is high enough, use again, but i suggest sucker punch. Each time you hurt the dog but are unsuccessful in capturing it, save the game. this is to ensure you don't kill the dog